We plan to continue our study of benzo(b)thiophene isoesteres of biologically active indoles, concentrating on melatonin and harmaline analogs. Structureal modifications of melatonin and analogous benzo(b)thiophene derivatives will be submitted for screening in a teleost fish screen. Addition work on structural modifications of the harmaline series will be tested in our own pharmacology laboratory. In addition, some studies on the chemistry of related heterocycles may develop some similar bioisosteres. The activity of these bioisosteres may provide some insight about receptor sites. BIBLIOGRAPHIC REFERENCES: Gamma-Valerolactones as Potential Anti-inflammatory Agents. E. Campaigne, R. L. Ellis and P. Raval, European Jour. Medicinal Chem., 12, 9-11 (1977). Synthesis of some 3-Hydroxy-5-pyridylpyrrole Derivatives. E. Campaigne, G. M. Shutske and J. C. Payne, Jour. Heterocyclic Chem., 14, 329-331 (1977).